CLASS GASTROPODA 
275 
in number. Lateral areas depressed. Gills median. Length, 23 mm. 
(Tryon and Pilsbry, Manual of Conchology.) 
Type in Academy of Sciences, St. Petersburg. Type locality, Patria, 
Ins Sitcha. 
Range. Known only from type locality. 
Ischnochiton interstinctus Gould, 1846 
Proceedings of the Boston Society of Natural History, 2:145. Report of the United 
States Exploring Expedition, Mollusca, 315; PI. 23, fig. 423. 
Testa solida, oblongo-ovalis, valde convexa, cinereo et nigro variegata, 
concentrice undulato-striata, granulis sparsis nigris aspersa, ad dorsum 
subcarinata et longitudinaliter nigro bifasciata; areis lateralibus vix dis- 
tinctis; margo aculeis inaequalibus curtis curvatis nigris et canescentibus 
indutus. Long., 1% 0 ; hit., ^ poll. (Gould.) 
Shell solid, elongated oval, slightly narrowed anteriorly, convexly ele¬ 
vated and slightly carinated along the back. General color a hoary white, 
here and there clouded with black, and with an interrupted black stripe 
each side of the summit. The surface is very minutely and irregularly 
granulated, so as to appear rugose under the lens; occasionally, and more 
especially on the lateral areas, these granules are shining jet black, so that 
the surface, when closely examined, appears sprinkled with isolated black 
dots. The valves are concentrically striated, the striae a little undulating, 
deep, distinct, and somewhat imbricated at the anterior margin, becoming 
fainter at the apex and sides. The lateral areas are very slightly raised, 
not distinctly defined, and with faint indications of a few radiating lines; 
a few minute, radiating lines may also be seen on the central areas, near 
the margin. Margin rather broad, clothed with short, unequal, slightly 
curved, black, and hoary spines, which are generally disposed in alternate 
clusters of black and white. Interior pale red and violet, somewhat iri¬ 
descent. (Gould.) 
Type in United States Museum. Type locality ? 
Range. Aleutian Islands to Sitka, Alaska, and Catalina Island, Cali¬ 
fornia. 
Described as Chiton incanus Gould. 
Ischnochiton radians Carpenter, 1892 
Tryon and Pilsbry, Manual of Conchology, 14:121 and 15:75; PI. 16, figs. 48, 49. 
Shell rather large, wide, elevated, the jugum acute; olivaceous, ele^ 
gantly radially streaked with brown. Interior blue-green with two brown 
rays. Valves delicate, flat, produced in the sinus in front; mucro in front 
[877] 
